This thesis explores how taxes, migration, and regional differences shape labour market outcomes in Belgium. The first chapter analyses marginal reforms to the personal income tax system, considering changes to both rates and brackets, and shows how these can affect public revenue, labour supply, and individual wellbeing. It identifies directions for reforms that best balance efficiency and equity. The second chapter examines wage differences between Belgian-born workers and various groups of foreign workers. While part of these gaps can be explained by differences in skills or job characteristics, a substantial share remains unexplained, particularly for non-European migrants, pointing to barriers such as occupational segregation and limited career progression. The third chapter investigates disparities across Belgium’s regions, highlighting the central role of education in increasing participation and reducing unemployment. Altogether, this thesis contributes to understanding the challenges of achieving fairer and more inclusive labour market outcomes in Belgium.